Resilient-clamping wrench with compressible slit ring inserts

ABSTRACT

A closed end wrench comprising a resilient clamp of hairpin form with a compressible, slit ring insert in the bight thereof, which slit ring has a circular periphery and a noncircular nut-engaging inner surface, in which torque is transmitted from the clamp to the insert by squeezing the legs of the clamp together and in which the maximum torque which can be transmitted is variably limited by adjustable stop means between the legs.

United States Patent lnventor Ross W. Bristol 1201 Ashford Drive. Blssell Hills, Mo. 63137 Appl. No. 781,822

Filed Dec. 6, 1968 Patented July 6, 1971 RESILlENT-CLAMPING WRENCH WITH COMPRESSIBLE SLIT RING INSERTS [0 Claims, 8 Drawing Figs.

US. Cl 81/64 Int. Cl B25!) 13/52 Field oiSearch.... 81/64, 65

[56] References Cited UNITED STATES PATENTS 276,064 4/1883 Morse 81/64 X 2,766,648 l0/l956 Jazwieck 81/64 X Primary Examiner-Travis S. McGehee Attorney-Charles A. Markham ABSTRACT: A closed end wrench comprising a resilient clamp of hairpin form with a compressible, slit ring insert in the bight thereof, which slit ring has a circular periphery and a noncircular nut-engaging inner surface, in which torque is transmitted from the clamp to the insert by squeezing the legs of the clamp together and in which the maximum torque which can be transmitted is variably limited by adjustable stop means between the legs.

RESILIENT-CLAMPING WRENCH WITH COMPRESSIBLE SLIT RING INSERTS This invention relates generally to hand wrenches and particularly to a closed end wrench or box wrench which may be slipped over tubing to engage tube-connecting nuts, and in which the amount of torque which may be applied to a nut is selectable.

Socket wrenches or other conventional closed end wrenches cannot be used to turn the nutsconnecting tubing to a tank or the like, as for example; the standard tube fitting nuts connecting copper tubing to liquid petroleum gas tanks or to gas consuming appliances. Consequently, open end wrenches are employed which at most engage only four sides and frequently only two sides of conventional hexagonal tubefitting nuts. Such tube-fitting nuts are usually brass and therefore relatively soft and if the fit of the open end wrench employed is not near perfect or if the wrench is not held perpendicular to the axis of the nut as force is applied, the nuts are frequently rounded ofi rendering them practically useless and requiring the tubing to be cut off and the nut replaced. Also, in the absence of any means of limiting the torque which can be applied to the nuts they are frequently pulled up so tight that the likelihood of rendering the nut useless when attempting to loosen it is greatly increased.

An object of the present invention is therefore the provision of a generally new and improved closed end hand wrench which is particularly adapted to, although by no means limited in use to, the service of connecting and disconnecting tubing to fluid fuel supply tanks, consuming appliances and the like.

A further object is to provide an inexpensive closed end wrench which is particularly adapted to, although not limited to, use in tightening or loosening relatively soft nonferrous nuts.

A further object is to provide a closed end hand wrench of simple and inexpensive construction having conveniently interchangeable inserts which closely fit and tightly grip all flat surfaces of a nut as torque is applied.

A further object is to provide a closed end wrench in which simulated ratchet action is achieved in a particularly simple and inexpensive manner.

A further object is to provide a closed end wrench in which means variably limiting the amount of torque which may be applied to a nut is provided at particularly low cost.

More specifically it is an object to provide a closed end wrench having a pair of spaced coextending legs connected at one end by a bight portion which embraces a nut-engaging insert having a circular periphery and interior nut-engaging flats and being slit so as to render it resiliently compressible, the handles being squeezed together to provide torque-transmitting friction between the bight portion and periphery of the insert and to tightly grip a nut as the wrench is turned in one direction and the squeezing pressure released as the wrench is turned in the opposite direction to permit the insert to slip in the bight portion thereby to provide simulated ratchet action.

With these and other objects in view my invention consists in the construction, arrangement, and combination of the various parts whereby the objects contemplated are achieved, as hereinafter fully described, illustrated in the drawings, and set forth in the appended claims.

In the drawings,

FIG. 1 is a side elevational view of a wrench constructed in accordance with the present invention shown associated with a tube-fitting nut;

FIG. 2 is a top plan view of the wrench and nut shown in FIG. 1;

FIG. 3 is an enlarged top plan view of the wrench shown in FIG. 1;

FIG. 4 is a partial cross-sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG.

FIG. 6 is a plan view of a nut-engaging insert with internal flat surfaces adapted to fit a hexagonal nut;

FIG. 7 is a cross-sectional view of the insert taken along line 7-7 of FIG. 6; and

FIG. 8 is a plan view of a nut-engaging insert with internal flat surfaces adapted to fit a square nut.

Referring now to the drawing in more detail, the wrench comprises a pair of spaced coextending legs 10 connected at one end by an arcuate bight portion 12 in which a nut-engags ing insert 14 of circular periphery is positioned. The wrench including the insert may be constructed of any material having suitable rigidity with the required resiliency. I prefer to construct it of a light weight metal such as an aluminum alloy having the required resiliency. Besides being light in weight the hazard of stricking sparks when using the wrench near explosive gases is minimized when using aluminum. Whatever material is used the relationship of the cross-sectional dimensions of the bight portion 12 to that of the handles 10 and to the length of handles 10 is such that the bight portion may be flexed slightly by an operators hand pressure when squeezing the legs 10 toward each other and the resiliency of the material such as to return to an original unstressed shape. In a free, unstressed condition the fit of insert 114 in the bight portion 12 is preferably such that the insert may be turned therein with a slight force.

The inside surface of the bight portion 12 is convex in cross section as indicated at 16 in FIGS. 4 and 5 and the peripheral surface of the insert 14 is concave as indicated at 18 whereby the insert is retained in the bight l2 .and whereby the area of the contiguous surfaces of the bight portion and inserts is increased. The diameter of one edge 20 of the insert 14 is made somewhat smaller than the opposite edge and is rounded off to facilitate the entry and removal of the insert.

The insert 14 is provided with internal flat surfaces 22 adapted to engage the flat surfaces of a nut. These flat surfaces may form a hexagon as shown in FIG. 6 or a square or any other configuration for that matter adapted to accommodate the shape of the nut to be turned or to merely fit the corners and adjacent portions of the flats thereof. The insert 14 has a section thereof removed thereby forming a gap 24, the width of the gap being substantially equal to the spacing of the legs 10. The insert 14 may be constructed of any suitable material having sufficient resiliency to permit its flexing sufficiently to solidly engage the surfaces and corners of a nut which is free fitting therein when the insert is in a free, unstressed condition and to completely recover its original shape when pressure is released.

When the wrench is to be used on nuts of relatively soft material such as brass or aluminum I prefer to construct the inserts of a brass or aluminum alloy having the required resiliency. When the wrench is to be used on steel nuts however the inserts are preferably constructed of a harder ferrous alloy of suitable resiliency.

The spacing of the legs 10 and the width of gap 24 in the insert 14 are such as to permit the passage therethrough of the tubing 26 to be connected so that the nut 27 surrounding the tubing may be entered axially into the insert. The diameter of tubing most commonly used for liquid petroleum gas lines extending from portable tanks to home and trailer appliances is A inch and 5/ 1 6 inch and the spacing of the legs and width of gap 24 would therefore be in this order of dimensions for this use. Wider spacing of the legs and a wider gap would, of course, be provided for larger diameter tubing which larger tubing would, incidentally, be connected by tube fittings having larger nuts.

When the wrench is to be used for other purposes than connecting or disconnecting tube fittings the width of the gap in the insert may be made considerably less as shown in insert 15 in FIG. 8, that is just sufficiently wide to permit a compression of the insert which will insure the firm gripping of the flat surfaces of a nut. In a free, unstressed condition the insert 14 and insert 15 are dimensioned as as to freely fit over nuts of corresponding, nominal size.

While the wrench will operate satisfactorily irrespective of where the gap is positioned around the circle of the insert, I prefer to position it along a diametral line intersecting opposed comers, as shown. A reason for this being that full contact with four flats and substantial contact with the other two flats of a hexagon nut are made even when the width of the gap approaches the width of a flat.

In order facilitate removal and insertion of the inserts the wrench is provided with a pivoted member 28 pivotally mounted on a pin 30 fixed in one of the legsl and having a cam surface 32 engaging a pin 34 fixed in the other of legs 10. The cam surface 32 has such configuration with respect to pivot 30 and pin 32 that when member 28 is pressed in a counterclockwise rotational direction the legs are forced apart slightly thereby opening the bight portion 12 slightly to permit easy removal or insertion of an insert. The cam surface 32 is terminated at one end in an abutment surface 36 which limits the counterclockwise rotation of member 28. At its other end the rate of fall of the cam surface is increased abruptly at 38 so that the member will be easily moved clockwise when handles 10 are pressed together in use.

A headless screw 40 extending transversely through one of the legs 10 near its free end and having a rounded end adapted to abut the inner surface of the other leg adjustably limits the movement of legs 10 toward each other. By thus variably limiting the movement of legs 10 toward each other I vary the friction which can be applied between the periphery of the insert and the inner surface of bight portion 12 thereby variably limiting the torque which can be applied to a nut. It will be understood that in operation only a slight flexing and contraction of the insert will occur with a nut engaged therein and that when the flat surfaces of the insert are solidly against the flat surfaces of a nut the friction between the insert and bight is increased by further squeezing the handles toward each other.

When the squeezing pressure on the legs 10 is released the wrench may be freely rotated without turning the nut due to slippage between the insert and surface of the bight 12. This permits tightening or loosening a nut with short swings of the handle without repositioning of the wrench on the nut, by applying a squeezing pressure when turning the wrench in one direction and by releasing the pressure when turning it in the opposite direction.

The foregoing description is intended to be illustrative and not limiting the scope of the invention being set forth in the appended claims.

I claim:

1. A device of the kind described comprising a pair of .f

spaced, coextending legs forming a handle, said legs being joined at one end by an integral arcuate bight portion, a circu lar nut-engaging insert embraced in said arcuate bight portion and rotatable therein, said circular insert having a noncircular central perforation adapted to receive in free-fitting engagement a noncircular nut and having a slot therein extending radially outward from said central perforation thereby to permit compression of said insert, said insert and said bight portion being sufiiciently resilient to permit an operator to compress surface portions of said insert defining said perforation therein into solid contact with surface portions of a normally free-fitting noncircular nut entered therein and to thereafter permit an increase in friction between said bight portion and said insert by manually squeezing said legs together.

2. A device as set forth in claim 1 which further includes means retaining said insert in said bight portion, and in which said insert is freely rotatable in either direction in said bight portion when said bight portion is in a free; unstressed condition whereby simulated ratchet action in either direction is attained by merely squeezing said handle legs together when turning the wrench applied to a nut in one direction and releasing the squeezing pressure when turning the wrench oppositely.

3. A device as set forth in claim 1 in which the width of said radial slot in said insert and the spacing of said legs is sufficient to permit the entry of a tube between the le sand through said slot into the noncircular perforation ll'l sai insert thereby to permit the axial entry of a tube-attaching nut into said noncircular perforation.

4. A device as set forth in claim 1 in which the circular peripheral surface of said insert and the contiguous inner surface of said embracing arcuate bight portion are curved with respect to an axial plane to form interfitting concave-convex surfaces whereby said insert is retained in said bight portion against axial movement and whereby removal or insertion of said insert is facilitated by requiring a minimum flexing of said bight portion in an opening direction.

5. A device as set forth in claim 1 which includes adjustable stop means limiting the movement of said adjacent legs toward each other whereby the friction between said insert and bight portion and therefore the torque which can be applied to a nut in said insert is adjustably limited.

6. A device as set forth in claim 1 which further includes manually operable means pivotally mounted on one of said legs and having a portion thereof engaging the other of said legs for moving said legs apart thereby to open said bight portion sufficiently to permit insertion or removal of said insert.

7. A device as set forth in claim 1 in which said legs are less resilient than said bight portion.

8. A device as set forth in claim 1 in which said legs and bight portion and said insert are flat and are formed as stampings from relatively thick flat sheet stock.

9. A device as set forth in claim 1 in which said device is constructed of a relatively hard aluminum alloy.

10. A device of the kind described comprising a pair of spaced coextending legs forming a handle, said legs being joined at one end by a resilient loop having an arcuate internal surface, a circular nut-engaging insert embraced and retained in said loop and rotatable therein, said circular insert having a noncircular central perforation therein adapted to receive a noncircular nut in free-fitting relationship and having a slot therein extending outward from said central perforation thereby to permit compression of said insert, and said insert and said loop being sufficiently resilient to permit an operator to compress surface portions defining said noncircular perforation into solid contact with surface portions of a normally free-fitting noncircular nut entered therein and to thereafter increase the friction between said loop and said insert to tighten or loosen the nut by manually squeezing said legs together. 

1. A device of the kind described comprising a pair of spaced, coextending legs forming a handle, said legs being joined at one end by an integral arcuate bight portion, a circular nut-engaging insert embraced in said arcuate bight portion and rotatable therein, said circular insert having a noncircular central perforation adapted to receive in free-fitting engagement a noncircular nut and having a slot therein extending radially outward from said central perforation thereby to permiT compression of said insert, said insert and said bight portion being sufficiently resilient to permit an operator to compress surface portions of said insert defining said perforation therein into solid contact with surface portions of a normally freefitting noncircular nut entered therein and to thereafter permit an increase in friction between said bight portion and said insert by manually squeezing said legs together.
 2. A device as set forth in claim 1 which further includes means retaining said insert in said bight portion, and in which said insert is freely rotatable in either direction in said bight portion when said bight portion is in a free, unstressed condition whereby simulated ratchet action in either direction is attained by merely squeezing said handle legs together when turning the wrench applied to a nut in one direction and releasing the squeezing pressure when turning the wrench oppositely.
 3. A device as set forth in claim 1 in which the width of said radial slot in said insert and the spacing of said legs is sufficient to permit the entry of a tube between the legs and through said slot into the noncircular perforation in said insert thereby to permit the axial entry of a tube-attaching nut into said noncircular perforation.
 4. A device as set forth in claim 1 in which the circular peripheral surface of said insert and the contiguous inner surface of said embracing arcuate bight portion are curved with respect to an axial plane to form interfitting concavo-convex surfaces whereby said insert is retained in said bight portion against axial movement and whereby removal or insertion of said insert is facilitated by requiring a minimum flexing of said bight portion in an opening direction.
 5. A device as set forth in claim 1 which includes adjustable stop means limiting the movement of said adjacent legs toward each other whereby the friction between said insert and bight portion and therefore the torque which can be applied to a nut in said insert is adjustably limited.
 6. A device as set forth in claim 1 which further includes manually operable means pivotally mounted on one of said legs and having a portion thereof engaging the other of said legs for moving said legs apart thereby to open said bight portion sufficiently to permit insertion or removal of said insert.
 7. A device as set forth in claim 1 in which said legs are less resilient than said bight portion.
 8. A device as set forth in claim 1 in which said legs and bight portion and said insert are flat and are formed as stampings from relatively thick flat sheet stock.
 9. A device as set forth in claim 1 in which said device is constructed of a relatively hard aluminum alloy.
 10. A device of the kind described comprising a pair of spaced coextending legs forming a handle, said legs being joined at one end by a resilient loop having an arcuate internal surface, a circular nut-engaging insert embraced and retained in said loop and rotatable therein, said circular insert having a noncircular central perforation therein adapted to receive a noncircular nut in free-fitting relationship and having a slot therein extending outward from said central perforation thereby to permit compression of said insert, and said insert and said loop being sufficiently resilient to permit an operator to compress surface portions defining said noncircular perforation into solid contact with surface portions of a normally free-fitting noncircular nut entered therein and to thereafter increase the friction between said loop and said insert to tighten or loosen the nut by manually squeezing said legs together. 